[vtkusers] Render() method acting slowly

[Richard Boardman]

Greetings everyone,

I have a series of spheres (100 or so) which I render in VTK through
Python. I then reposition all of these spheres, and re-render the window
using the VTK Render() method. With the phi and theta resolution of the
spheres set to around 30 each, it will only update the display at around 2
frames per second. If I reduce the phi and theta resolutions of the sphere
to just 3, then the update speed is better (~15fps) but still slower than
I would expect, and it is once more unbearably slow with 300 spheres or
so. However, if I rotate, pan or zoom the scene with the mouse I get the
kind of frame rate I would expect, around 100fps, and this is the case
even on much more complex scenes.

Are there any other ways to 'move' these spheres around which might be
quicker? After browsing the class documentation for the render window
stuff I see nothing apparent. My platform is SuSE Linux 8.1 on an Athlon
XP 1800, graphics adapter is a high-end GeForce 4 using the nVidia SuSE
drivers.

Just out of curiosity, I removed the spheres and plotted the positions
with the vtkLineSource method - again, this is quicker (around the same
speed as the super-low resolution spheres) but unacceptable with larger
datasets. Is there something obvious that I'm doing wrong?

Thanks in advance,

Richard Boardman                                o o o o o
Computational Engineering and Design Group      o o o o o
School of Engineering Sciences                  o o o o o
University of Southampton                       o o o o o
United Kingdom                                  o o o o o